Differential interferometric SAR (DInSAR) technique has been widely known as wide range of land subsidence measurement method. However, the displacement is obtained only along the radar line-of-sight (LOS) direction. Thus, in this paper, we merged the results from PSI and geodetic deformation measurements (GPS and leveling) to estimate the three-dimensinal displacement velocities of Kansai International Airport. We compared the estimated results with GPS/leveling survey data. The root mean squared errors (RMSEs) were 7, 14 and 16 mm/year for the east-west, north-south and vertical components, respectively. It was found our proposed method is effective for land subsidence monitoring.
Nowadays, products of satellite imagery are used in many research fields. To verify accuracy of products, inverse estimation for radiance is applied by ray tracing using physical model. Usually, forest model which combined simple shaped tree has been used as a physical model. However, the model can't represent complex structure of a forest. Voxel model is one suitable model that can represent complex structures of a forest. In this research, red band of aerial images was simulated by ray tracing of sunlight using a voxel model. The test area was selected evergreen broad-leaf forests, evergreen needle-leaf forest and deciduous broad-leaved forest in the deciduous period. At evergreen broad-forests and evergreen needle-leaf forest, shadow and shade was simulated. At deciduous broad-leaved forest, scattering cross section was simulated. As a result, the correlation coefficient was 0.638 at evergreen broad-leaf forests, 0.729 at evergreen needle-leaf forest and 0.630 at deciduous broad-leaved forest. Our proposal method was suitable to simulate reflected sunlight using a voxel model in a forest because the correlation coefficient showed over 0.6. For future works, we improve our method by consider multiple reflections and atmospheric effect.
Research and development on smart agriculture is being promoted to solve the problems of efficiency and labor saving of agricultural work. This paper describes relationship between the results of monitoring plant height and NDVI using UAV and soil nutrients. Focusing on the fact that the distribution of NDVI is different even in one rice field, the relationship with soil nutrients (phosphate, potassium, calcium, magnesium) was investigated. As a result, it was found that the activity of paddy rice is increased by absorbing phosphate in the soil.
The Quasi-Zenith Satellite System “MICHIBIKI” launched service on November 1, 2018.
“MICHIBIKI” provides Satellite Positioning services, Positioning Augmentation services, Disaster and Crisis Management Reporting services, and so on.
In addition to showing the outline of these services, this paper shows examples of the use of “MICHIBIKI” in various fields such as agriculture, location-based services and distribution.
This paper also shows the contents of the 7-satellite constellation that allows sustainable positioning around FY2023.